Anyone know how to stretch an ARP 2000 rod bolt?

I don't wanna spend 160 bucks to get them stretched again, so i'm going to tackle it myself. I have vague knowledge on stretching bolts, but if anyone has a good link for video/read or some knowledge to drop, it would be greatly appreciated.

 

Specs for ej257 bolts Manley part #42350

 

http://manleyperformance.com/dl/tech/rod-hbeam.pdf

Edited November 13, 2020 by Tehnation

Do you mean how to measure the stretch when torquing them up correctly? You need a stretch gauge or 1 of those tools you stick a dial indicator in.

I ordered one of these to measure stretch.

 

https://www.summitracing.com/parts/sum-900015

I guess it's pretty self explanatory ... but was wondering if there was some advice and or tips.

I usually install bolts finger tight or snug then take a pre measurement. Since the torque range is 55-65 and the difference in the torque wrenches. I would just sneak up on the stretch. Torque both bolts to 40-45 and check the stretch value. If low add 5 or 2 then recheck. Depending on the torque wrench you have you might be low or high on your wrench number to get the stretch. If all went well you should be around 60ish to get your stretch. Most use straight 30 weight oil not 5w30 etc. With a little practice be no problem

Is that stretch within elasticity? Does the bolt bounce back or is it permanent? I need to plastigage first, and I believe the bolts are reusable. I'm just not sure. From what I've seen you are right and torquing it to spec will indeed give the proper stretch, so torquing to around 60 should yield the proper stretch. I may use old bolts and just plastigage with them and do final assembly with new bolts to avoid any issues.

Is that stretch within elasticity? Does the bolt bounce back or is it permanent? I need to plastigage first, and I believe the bolts are reusable. I'm just not sure. From what I've seen you are right and torquing it to spec will indeed give the proper stretch, so torquing to around 60 should yield the proper stretch. I may use old bolts and just plastigage with them and do final assembly with new bolts to avoid any issues.

 

this pdf by a rod manufacturer indicates you can torque and re-use several times before the arp2000 bolts are exhausted - https://soaraperformance.com/wp-content/uploads/2017/01/ARP-conrod-bolts-tightening.pdf

 

Also note 5 times torque'ing to get proper stretch.

I had to do this once on an old Mercedes diesel rebuild. The rod bolts had machined pockets in both ends for measuring stretch. What I came up with was to stick two 0.250 ball bearings on the ends of the bolts. Then you can use a regular micrometer to measure length. Modern ball bearings (visit your local bike shop) are outstanding for tolerance but it doesn't really matter since it is a relative measure you are looking for.

 

If memory serves, I think I just stuck the bearings into the pockets with grease after hand assembly of the rods. A better solution (with lots of applications) is to use heat shrink tubing to make little sleeves to hold the ball bearings on the micrometer anvil and/or strike so you don't have to futz around with the balls dropping off.

 

This is a quick and accurate way to turn a regular mic into a `ball mic' for measuring things like bearing shell thickness, by the way.

Edited December 1, 2020 by birkhoff
For clarity

I used one of these

 

https://www.summitracing.com/parts/sum-900015

 

its meant to go into those pockets, so no need for ball bearings. You zero it, then measure the stretch, was very easy actually.